#define _CRT_SECURE_NO_WARNINGS 1

class Solution {
public:
    void reverseString(vector<char>& s) {
        int left = 0;
        int right = s.size() - 1;
        while (left != right && left - 1 != right)
        {
            swap(s[left], s[right]);
            ++left;
            --right;
        }
    }
};